Views: 0 Author: Kath Publish Time: 2024-09-06 Origin: Site
ASTM A106 high temperature seamless carbon steel norminal pipe is the standard of the American Society of Testing and Material, equivalent to the ASME SA-106 standard. It divides into Grade A, Grade B and Grade C according to ifferent chemical compositions. C content can correspond to GB/T 699 high quality structural steel #25 steel, #30 steel and #35 steel. Steel pipe manufacturing includes two processes:cold-drawn and hot rolled. In addition to the different production processes, the two are different in precision, surface quality, minimum size, mechanical properties and organizational structure. It’s widely used in industries such as petroleum, chemical, boiler, automobile, aerospace and military industry.
China | Grade | American | Grade |
GB/T 699 | #25, 30, 35 | ASTM | A106 |
Grade | #25 | A106 |
C | 0.22~0.29 | <=0.25 |
Mn | 0.50~0.80 | 0.27~0.93 |
P | 0.035 | 0.035 |
S | 0.035 | 0.035 |
Si | 0.17~0.37 | >=0.10 |
Cu | 0.25 | <=0.40 |
Ni | 0.30 | <=0.40 |
Cr | 0.25 | <=0.40 |
Mo | ----- | <=0.15 |
V | ----- | <=0.08 |
Grade | Tensile strength Rm (Mpa) | Yield strength Rp (Mpa) | Hardness HBW |
#25 | >=450 | >=275 | <=170 |
A106 | >=330 | >=205 | --------- |
(1) Low carbon steel, carbon content <0.25%
(2) Medium carbon steel, carbon content 0.25%~0.6%
(3) High carbon steel, carbon content >0.6%
ASME SA-106 carbon steel pipe fittings are medium carbon steel, containing 0.25~0.35% carbon content. The welding performance changes with the increase of carbon content. When the carbon content is greater than 0.22%, the welding performance is poor, and it is easy to break. Stress crackss will affect the performance of the material.
Welding material
Select welding materials according th the American Welding Society standard AWS A5.1 or GB/T 5118,GB/T 8110. If you choose arc welding, treat the electrode according the electrode standard before welding.
The process includes welding line energy, preheating temperature and post-weld heat treatment etc.
(1) When using submerged arc welding and the material thickness is greatly than 30mm, it is recommended to quickly perform 2 hour dehydrogenation annealing at 200~280℃ after welding.
(2) When the material thickness is large, the upper limit temperature and longer insulation time should be used.
(3) After the weld is filled, it needs to be cooled to the preheating temperature, and dehydrogenation annealing is recommended.
(4) When the weld must be cooled the preheating temperature and dehydrogenation annealing cannot be performed, it’s recommended to perform crack inspection on the weld.
(5) If the cracks are generated when grinding the weld surface, non-destructive testing is not allowed after the weld is cooled , and it should be after 48 hours.
